Electrical equipment (e.g., electrical cables, electrical connectors, electrical receptacles, electrical devices) are used in a large number of applications. Electrical equipment often contain components requiring electrical power, and in some cases the required electrical power can have relatively high voltage and current ratings. Receptacles have been designed to provide power to some such devices. Often, receptacles are designed with mechanical interlocking features to ensure that a connector from the electrical device is properly inserted into the receptacle. However, as described further below, such mechanical interlocking features do not provide electrical testing features.
Refrigerated shipping containers (also called reefer containers) are one example of a portable electrical device that requires power. Refrigerated shipping containers are used to ship goods throughout the world. Such refrigerated shipping containers can be transported on trains, trucks, and ships and the containers are often stationed at ports, warehouses, and distribution centers. While the refrigerated containers are located in these various modes of transportation and storage, they often need electrical power to operate the refrigeration unit of the container. The refrigeration units in refrigerated shipping containers typically operate at relatively high voltage and current ratings. For example, many refrigerated shipping containers operate at 480 volts AC and 32 amps.